Automobile interior adhesive and preparation method thereof

Abstract

The application discloses an adhesive for automobile interior decoration and a preparation method thereof. In one aspect, the application provides an adhesive for automobile interior decoration, and the adhesive is prepared from the following components in parts by weight: 18-28 parts of SBS thermoplastic elastomer, 8-14 parts of SIS thermoplastic elastomer, 48-56 parts of high-crystallinity polyester polyurethane prepolymer, 6-12 parts of alkyl sulfonic acid phenyl ester, 12-24 parts of tackifying resin, 8-16 parts of polyurethane acrylic resin, 12-18 parts of bifunctional acrylate monomer resin, 6-10 parts of light-curing acrylic monomer, 2-6 parts of organic phosphorus photoinitiator, 1-4 parts of hindered phenolic antioxidant and 4-8 parts of nano titanium dioxide. In another aspect, the application further provides a preparation method of the adhesive for automobile interior decoration. The adhesive has relatively low cost, excellent moisture permeability and waterproof performance, excellent oil-solvent resistance and excellent light and heat aging resistance.

Description

Technical Field

[0001] This application relates to the field of adhesive technology, and in particular to an adhesive for automotive interiors and its preparation method. Background Technology

[0002] Automotive interior refers to the interior trim of components such as the car roof, carpets, floor mats, dashboard, door panels, seats, trunk rack, and spare tire cover. During the manufacturing process, it is usually made of multiple layers of non-metallic materials (such as artificial leather, polyurethane foam, latex sponge, cloth, velvet, wood, wood-plastic composite materials, ABS, PP, and other functional plastic parts) in composite molding, with various adhesives being the main connecting materials.

[0003] Currently, the adhesives used in automotive interior trim mainly fall into three categories: solvent-based adhesives, water-based interior trim adhesives, and solvent-free adhesives. Solvent-based adhesives have been gradually phased out due to environmental concerns. Water-based automotive interior trim adhesives, primarily acrylic water-based adhesives, offer advantages such as being non-toxic, non-flammable, environmentally friendly, and odorless, and are currently widely used. However, acrylic water-based adhesives contain a certain amount of water as a solvent, requiring a certain drying and curing time. After bonding, they need to be secured with tape or clamps, and can only be removed after a period of drying and curing to establish sufficient adhesion, making the bonding process relatively complex.

[0004] Solvent-free adhesives, primarily solvent-free pressure-sensitive adhesives and hot-melt polyurethane adhesives, offer fast application and immediate initial bonding, eliminating the need for tapes and clamps, making them convenient to use. Furthermore, these solvent-free adhesives contain no solvents, eliminating the problems of solvent evaporation and precipitation, thus being more environmentally friendly. Hot-melt polyurethane adhesives, in particular, exhibit excellent initial adhesion, high sustained bond strength, a wide range of adhesive options, and good compatibility with painted surfaces, making them a promising new type of adhesive for automotive interiors. However, existing hot-melt polyurethane adhesives also suffer from drawbacks such as poor resistance to oily contaminants, insufficient high-temperature aging resistance, and inadequate moisture permeability and waterproofing.

[0005] Therefore, designing a hot-melt polyurethane adhesive with excellent resistance to oily solvents, superior moisture permeability and waterproofing, and good resistance to photo- and heat aging is an urgent problem to be solved in this field. Summary of the Invention

[0006] In order to solve at least one of the above-mentioned technical problems, and to develop a relatively low-cost hot-melt polyurethane adhesive with excellent moisture permeability and waterproof performance, excellent resistance to oil solvents, and excellent resistance to photothermal aging, this application provides an adhesive for automotive interiors and a method for preparing the same.

[0007] On one hand, this application provides an adhesive for automotive interior trim, wherein the weight proportions of each component of the adhesive include: 18-28 parts of SBS thermoplastic elastomer, 8-14 parts of SIS thermoplastic elastomer, 48-56 parts of highly crystalline polyester polyurethane prepolymer, 6-12 parts of alkyl sulfonate phenyl ester, 12-24 parts of tackifying resin, 8-16 parts of polyurethane acrylic resin, 12-18 parts of bifunctional acrylate monomer resin, 6-10 parts of photocurable acrylic monomer, 2-6 parts of organophosphorus photoinitiator, 1-4 parts of hindered phenolic antioxidant, and 4-8 parts of nano titanium dioxide.

[0008] Optionally, the adhesive components are proportioned in the following weight ratios: 22-24 parts SBS thermoplastic elastomer, 10-12 parts SIS thermoplastic elastomer, 50-52 parts highly crystalline polyester polyurethane prepolymer, 8-10 parts alkyl sulfonate phenyl ester, 18-20 parts tackifying resin, 10-12 parts polyurethane acrylic resin, 14-16 parts bifunctional acrylate monomer resin, 6-7 parts photocurable acrylic monomer, 3-4 parts organophosphorus photoinitiator, 2-3 parts hindered phenolic antioxidant, and 6-7 parts nano titanium dioxide.

[0009] Optionally, the SBS thermoplastic elastomer is selected from SBS thermoplastic elastomers with a diblock content of 42-48%.

[0010] Optionally, the SIS thermoplastic elastomer is selected from SIS thermoplastic elastomers with an SI content of 25-30%.

[0011] Optionally, the highly crystalline polyester-type polyurethane prepolymer is selected from a prepolymer prepared by reacting poly(1,6-hexanediol dodecyl diacid) and / or poly(1,6-hexanediol adipate) with a polyisocyanate.

[0012] Optionally, the tackifying resin may be a petroleum resin.

[0013] Optionally, the bifunctional acrylate monomer resin is selected from 1,6-hexanediol diacrylate and / or tripropylene glycol diacrylate.

[0014] Optionally, the photocurable acrylic monomer is selected from one or more of cyclohexyl methacrylate, benzyl acrylate, or isobornyl acrylate.

[0015] Optionally, the adhesive may further include a methoxy-linear polysiloxane, wherein the amount of the methoxy-linear polysiloxane added is 6 to 8 parts.

[0016] On the other hand, this application also provides a method for preparing the above-mentioned adhesive for automotive interiors, including the following steps:

[0017] S1. Accurately weigh each component according to the proportions;

[0018] S2. Mix SBS thermoplastic elastomer, SIS thermoplastic elastomer and alkyl sulfonate phenyl ester, and knead at 160~170℃ for more than 60 minutes to obtain a compound.

[0019] S3. The compound obtained in step S2 and the remaining materials are subjected to high-speed shearing and stirring at a vacuum of 0.06~0.08Mpa at room temperature and at a speed of 6000~8000rpm for more than 60 minutes to obtain an adhesive for automotive interiors.

[0020] In summary, the present invention has at least one of the following beneficial technical effects:

[0021] 1. This application uses a highly crystalline polyester-type polyurethane prepolymer as the main adhesive, supplemented with SBS thermoplastic elastomer and SIS thermoplastic elastomer, and mixes them in a certain proportion to form a stable network structure colloidal network. After curing, it can form an interpenetrating network structure adhesive film, which can effectively improve the peel strength, tack, and moisture permeability and waterproof performance of the adhesive after curing. In addition, the stable interpenetrating network structure adhesive film formed by this application also has good chemical stability and excellent resistance to oil and grease solvents.

[0022] 2. This application uses an environmentally friendly alkyl sulfonate plasticizer, which, when incorporated into the adhesive system of this application, can effectively improve the low-temperature flexibility of the adhesive and make the adhesive easier to apply. In addition, this application adds a certain amount of tackifying resin, which, in the presence of the alkyl sulfonate plasticizer, can be better compatible with the adhesive system of this application and can effectively improve the initial tack and holding power of the adhesive.

[0023] 3. The adhesive of this application incorporates a specific acrylate-based photoinitiating curing system. With the use of antioxidants, it can cure under photothermal conditions, thereby effectively improving the adhesive strength under photothermal conditions and enhancing the adhesive's resistance to photothermal aging. Furthermore, the specific acrylate-based photoinitiating curing system used in this application, after slow curing under photothermal conditions, can also form an acrylate-based curing network in the adhesive, further improving the adhesive's moisture permeability, waterproofing, and resistance to oily solvents after curing.

[0024] 4. The raw materials used in the adhesive of this application are readily available, the preparation method is relatively simple, and the preparation cost is relatively low. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the embodiments.

[0026] This application designs an adhesive for automotive interior trim, wherein the weight proportions of the components of the adhesive include: 18-28 parts of SBS thermoplastic elastomer, 8-14 parts of SIS thermoplastic elastomer, 48-56 parts of highly crystalline polyester polyurethane prepolymer, 6-12 parts of alkyl sulfonate phenyl ester, 12-24 parts of tackifying resin, 8-16 parts of polyurethane acrylic resin, 12-18 parts of bifunctional acrylate monomer resin, 6-10 parts of photocurable acrylic monomer, 2-6 parts of organophosphorus photoinitiator, 1-4 parts of hindered phenolic antioxidant, and 4-8 parts of nano titanium dioxide.

[0027] The method for preparing the above-mentioned adhesive for automotive interior trim in this application includes the following steps:

[0028] S1. Accurately weigh each component according to the proportions;

[0029] S2. Mix SBS thermoplastic elastomer, SIS thermoplastic elastomer and alkyl sulfonate phenyl ester, and knead at 160~170℃ for more than 60 minutes to obtain a compound.

[0030] S3. The compound obtained in step S2 and the remaining materials are subjected to high-speed shearing and stirring at a vacuum of 0.06~0.08Mpa at room temperature and at a speed of 6000~8000rpm for more than 60 minutes to obtain an adhesive for automotive interiors.

[0031] To address the problems existing in the prior art, this application improves the polyurethane hot melt adhesive system. First, this application adds a colloid primarily composed of SBS thermoplastic elastomer and SIS thermoplastic elastomer. Second, this application designs a specific acrylate-based photoinitiated curing system. The SBS and SIS thermoplastic elastomers, after mixing, can form a stable network-structured colloidal network. This network can be fused with the polyurethane prepolymer after high-speed shear mixing. After the polyurethane prepolymer cures, it forms a stable interpenetrating network adhesive film with excellent chemical stability, solvent resistance, and good waterproof performance. The acrylate-based photoinitiated curing system, incorporated into the adhesive system after high-speed shear mixing, can slowly cure under the influence of light and heat after the adhesive has cured, forming another interpenetrating network structure, which can further improve the various properties of the adhesive. This application, with its triple cross-linked network design, effectively solves the problems existing in the prior art.

[0032] The following are embodiments of this application.

[0033] All the main raw materials used in the embodiments of this application are commercially available.

[0034] Among them, SBS thermoplastic elastomer with diblock content of 42-48% and 32-38% was purchased from Hunan Baling Petrochemical; SIS thermoplastic elastomer with SI content of 25-30% and 15-18% was purchased from Hunan Baling Petrochemical; highly crystalline polyester polyurethane prepolymer, K1230 type, and T80 polyester polyurethane prepolymer made by adding MOCA were purchased from Jiangsu Qianmeite Polyurethane New Materials Co., Ltd.; highly crystalline polyester polyurethane prepolymer, prepared by reacting polydodecyl diacid-1,6-hexanediol ester and polyadipate-1,6-hexanediol ester with polyisocyanate at a mass ratio of 1.5:1, was customized and purchased from Jiangsu Qianmeite Polyurethane New Materials Co., Ltd. Alkyl sulfonate phenyl ester, T50, purchased from Shandong Kejian Chemical Co., Ltd.; Tackifying resin, C5 petroleum resin, purchased from Shenzhen Yoshida Chemical Co., Ltd.; Polyurethane acrylate resin, purchased from Merck Chemicals; 1,6-hexanediol diacrylate and tripropylene glycol diacrylate, purchased from Merck Chemicals; Isoborneol acrylate, purchased from Shanghai Demao Chemical Co., Ltd.; Organophosphorus photoinitiator, TPO, purchased from Merck Chemicals; Antioxidant, Antioxidant 1010, purchased from Dongguan Xingyuan Chemical Co., Ltd.; Nano titanium dioxide, 80~200nm, purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; Methoxy linear polysiloxane, PMOS, purchased from Shandong Binruit New Materials Co., Ltd.

[0035] The method for preparing the adhesive for automotive interior trim according to the embodiments of this application includes the following steps:

[0036] S1. Accurately weigh each component according to the proportions;

[0037] S2. Mix SBS thermoplastic elastomer, SIS thermoplastic elastomer and alkyl sulfonate phenyl ester, and knead at 160~170℃ for 60 min to obtain the compound.

[0038] S3. The compound obtained in step S2 and the remaining materials are subjected to high-speed shearing and stirring at 7500 rpm for 60 minutes under a vacuum of 0.06~0.08 MPa at room temperature. The mixture is then discharged to obtain the adhesive for automotive interiors.

[0039] Example 1

[0040] The adhesive for automotive interior trim in this embodiment comprises the following components in the following weight proportions: 18 parts of SBS thermoplastic elastomer (diblock content 32~38%), 8 parts of SIS thermoplastic elastomer (SI content 15~18%), 48 parts of K1230 type highly crystalline polyester polyurethane prepolymer, 6 parts of alkyl sulfonate phenyl ester, 12 parts of tackifying resin, 8 parts of polyurethane acrylic resin, 12 parts of 1,6-hexanediol diacrylate, 6 parts of isobornyl acrylate, 2 parts of TPO photoinitiator, 1 part of antioxidant, and 4 parts of nano titanium dioxide.

[0041] Example 2

[0042] The adhesive for automotive interior trim in this embodiment comprises the following components in the following weight proportions: 28 parts of SBS thermoplastic elastomer (diblock content 32~38%), 14 parts of SIS thermoplastic elastomer (SI content 15~18%), 56 parts of K1230 type highly crystalline polyester polyurethane prepolymer, 12 parts of alkyl sulfonate phenyl ester, 24 parts of tackifying resin, 16 parts of polyurethane acrylic resin, 18 parts of 1,6-hexanediol diacrylate, 10 parts of isobornyl acrylate, 6 parts of TPO photoinitiator, 4 parts of antioxidant, and 8 parts of nano titanium dioxide.

[0043] Example 3

[0044] The adhesive for automotive interior trim in this embodiment comprises the following components in the following weight proportions: 22 parts of SBS thermoplastic elastomer (diblock content 32~38%), 10 parts of SIS thermoplastic elastomer (SI content 15~18%), 50 parts of K1230 type highly crystalline polyester polyurethane prepolymer, 8 parts of alkyl sulfonate phenyl ester, 18 parts of tackifying resin, 10 parts of polyurethane acrylic resin, 14 parts of 1,6-hexanediol diacrylate, 6 parts of isobornyl acrylate, 3 parts of TPO photoinitiator, 2 parts of antioxidant, and 6 parts of nano titanium dioxide.

[0045] Example 4

[0046] The adhesive for automotive interior trim in this embodiment comprises the following components in the following weight proportions: 24 parts of SBS thermoplastic elastomer (diblock content 32~38%), 12 parts of SIS thermoplastic elastomer (SI content 15~18%), 52 parts of K1230 type highly crystalline polyester polyurethane prepolymer, 10 parts of alkyl sulfonate phenyl ester, 20 parts of tackifying resin, 12 parts of polyurethane acrylic resin, 16 parts of 1,6-hexanediol diacrylate, 7 parts of isobornyl acrylate, 4 parts of TPO photoinitiator, 3 parts of antioxidant, and 7 parts of nano titanium dioxide.

[0047] Example 5

[0048] The adhesive for automotive interior trim in this embodiment comprises the following components in the following weight proportions: 23 parts of SBS thermoplastic elastomer (diblock content 32-38%), 11 parts of SIS thermoplastic elastomer (SI content 15-18%), 51 parts of K1230 type highly crystalline polyester polyurethane prepolymer, 9 parts of alkyl sulfonate phenyl ester, 19 parts of tackifying resin, 11 parts of polyurethane acrylic resin, 15 parts of 1,6-hexanediol diacrylate, 6.5 parts of isobornyl acrylate, 3.5 parts of TPO photoinitiator, 2.5 parts of antioxidant, and 6.5 parts of nano titanium dioxide.

[0049] Example 6

[0050] The difference between this embodiment and embodiment 5 is that 7 copies of PMOS are added.

[0051] Example 7

[0052] The difference between this embodiment and Embodiment 6 is that the SBS thermoplastic elastomer used is a product with a diblock content of 42-48%.

[0053] Example 8

[0054] The difference between this embodiment and Embodiment 7 is that the SIS thermoplastic elastomer is a product with an SI content of 25-30%.

[0055] Example 9

[0056] The difference between this embodiment and Example 8 is that the highly crystalline polyester polyurethane prepolymer is a customized product prepared by reacting polydodecyl diacid-1,6-hexanediol ester and polyadipate-1,6-hexanediol ester with polyisocyanate in a mass ratio of 1.5:1.

[0057] Example 10

[0058] The difference between this embodiment and Embodiment 9 is that the bifunctional acrylate monomer resin is a product of 1,6-hexanediol diacrylate and tripropylene glycol diacrylate mixed in a 1:1 mass ratio.

[0059] Comparative Example 1

[0060] This application uses 3M's RPU reactive one-component moisture-curing polyurethane hot melt adhesive as Comparative Example 1.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 10 is that an equal amount of SBS thermoplastic elastomer is used to replace the SIS thermoplastic elastomer.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 10 is that SBS thermoplastic elastomer and SIS thermoplastic elastomer are not added.

[0065] Comparative Example 4

[0066] The difference between this comparative example and Example 10 is that no bifunctional acrylate monomer resin, photocurable acrylic monomer, or organophosphorus photoinitiator is added.

[0067] Adhesion performance testing:

[0068] The adhesives of Examples 1 to 10 and Comparative Examples 1 to 4 of this application were tested for relevant properties, including initial tack, peel strength after curing, water resistance, oil solvent resistance and photothermal aging resistance.

[0069] The samples were bonded together, consisting of 2.5×25cm TPU and ABS boards. To facilitate solvent resistance testing, the adhesive thickness was 5mm. Initial tack was tested to measure the adhesive strength after bonding, and peel strength was tested after 4 hours of bonding.

[0070] Among them, the initial tack and peel strength after curing were tested according to the method described in GB / T 2790-1995 for 180° peel strength;

[0071] Moisture permeability and waterproof performance: The bonded samples were immersed in water for 120 hours and then the 180° peel strength of the bonded samples was tested.

[0072] Oil and solvent resistance: Gasoline and salad oil were prepared, and the bonded samples were immersed in gasoline and salad oil for 72 hours respectively. Then the 180° peel strength of the bonded samples was tested.

[0073] Photothermal aging: The aging treatment was carried out at a temperature of 80℃, a humidity of 85%, and an ultraviolet intensity of 0.45W / m. 2 Under these conditions, the treatment lasted for 15 days.

[0074] The test results are shown in Tables 1 and 2 below.

[0075] Table 1. Adhesion performance test data of Examples 1-10 and Comparative Examples 1-4

[0076] ;

[0077] Table 2. Adhesion performance test data of Examples 1-10 and Comparative Examples 1-4 after aging.

[0078] ;

[0079] As can be seen from the data in Tables 1 and 2, the adhesives of Examples 1-10 of this application exhibit significantly better initial tack and peel strength after curing than 3M's one-component moisture-curing polyurethane hot melt adhesive in bonding TPU and ABS sheets. Furthermore, their moisture permeability, waterproofing, and oil solvent resistance are also significantly superior to those of 3M's one-component moisture-curing polyurethane hot melt adhesive. In addition, after photothermal aging, the peel strength of the adhesives of Examples 1-10 of this application shows a significant improvement, while the peel strength of 3M's one-component moisture-curing polyurethane hot melt adhesive shows a significant decrease. Moreover, after photothermal aging, the moisture permeability, waterproofing, and oil solvent resistance of the adhesives of this application remain excellent, while 3M's one-component moisture-curing polyurethane hot melt adhesive shows a relatively significant performance decline. Therefore, the adhesives of this application are significantly superior to existing market products in terms of initial tack, cured bond strength, moisture permeability, waterproofing, and oil solvent resistance, and their photothermal aging resistance is even better than that of existing market products.

[0080] A comparison of the data from Examples 1-10 in Tables 1 and 2 shows that, after optimizing the composition of the highly crystalline polyester-type polyurethane prepolymer and the product parameters of the SBS and SIS thermoplastic elastomers, the relevant properties of the adhesive can be significantly improved. Furthermore, the performance of the adhesive is also improved to some extent after optimizing the component ratio; and the addition of PMOS further enhances its resistance to photothermal aging.

[0081] The data in Tables 1 and 2, comparing the data from Example 10 with those from Comparative Examples 2-4, show that the triple interpenetrating crosslinking network system designed in this application is the core of the excellent performance of the adhesive. Without any one of the crosslinking network systems, it is difficult to obtain excellent adhesive performance. Furthermore, in the design of this application, the thermoplastic elastomer crosslinking network system requires SBS thermoplastic elastomer and SIS thermoplastic elastomer to be mixed in a certain ratio to obtain good results; using only SBS thermoplastic elastomer cannot achieve the corresponding adhesive effect.

[0082] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An adhesive for automotive interior trim, characterized in that, The adhesive components are formulated in the following weight proportions: 18-28 parts SBS thermoplastic elastomer, 8-14 parts SIS thermoplastic elastomer, 48-56 parts highly crystalline polyester polyurethane prepolymer, 6-12 parts alkyl sulfonate phenyl ester, 12-24 parts tackifying resin, 8-16 parts polyurethane acrylic resin, 12-18 parts bifunctional acrylate monomers, 6-10 parts photocurable acrylic monomers, 2-6 parts organophosphorus photoinitiator, 1-4 parts hindered phenolic antioxidant, and 4-8 parts nano-titanium dioxide; the SBS thermoplastic elastomer is selected with a diblock content of 42%. The product contains 48% SBS thermoplastic elastomer, wherein the SIS thermoplastic elastomer is selected from SIS thermoplastic elastomers with an SI content of 25-30%, the highly crystalline polyester polyurethane prepolymer is selected from prepolymers obtained by reacting poly(1,6-hexanediol dodecyl diacid) and poly(1,6-hexanediol adipate) with polyisocyanates, the bifunctional acrylate monomer is selected from 1,6-hexanediol diacrylate and / or tripropylene glycol diacrylate, and the photocurable acrylic monomer is selected from one or more of cyclohexyl methacrylate, benzyl acrylate, or isobornyl acrylate.

2. The adhesive for automotive interior trim according to claim 1, characterized in that, The adhesive components are formulated in the following weight proportions: 22-24 parts SBS thermoplastic elastomer, 10-12 parts SIS thermoplastic elastomer, 50-52 parts highly crystalline polyester polyurethane prepolymer, 8-10 parts alkyl sulfonate phenyl ester, 18-20 parts tackifying resin, 10-12 parts polyurethane acrylic resin, 14-16 parts bifunctional acrylate monomer, 6-7 parts photocurable acrylic monomer, 3-4 parts organophosphorus photoinitiator, 2-3 parts hindered phenolic antioxidant, and 6-7 parts nano titanium dioxide.

3. The adhesive for automotive interior trim according to claim 1, characterized in that, The tackifying resin is selected from petroleum resin.

4. The adhesive for automotive interior trim according to claim 1, characterized in that, The adhesive also includes a methoxy-linear polysiloxane, wherein the amount of the methoxy-linear polysiloxane added is 6 to 8 parts.

5. A method for preparing an adhesive for automotive interior trim as described in claim 1, characterized in that, Includes the following steps: S1. Accurately weigh each component according to the proportions; S2. Mix SBS thermoplastic elastomer, SIS thermoplastic elastomer and alkyl sulfonate phenyl ester, and knead at 160~170℃ for more than 60 minutes to obtain a compound. S3. The compound obtained in step S2 and the remaining materials are subjected to high-speed shearing and stirring at a vacuum of 0.06~0.08MPa at room temperature and at a speed of 6000~8000rpm for more than 60 minutes to obtain an adhesive for automotive interiors.